'Unless' in the Bible

Be mindful, therefore, of the height from which you have fallen. Repent at once, and act as you did at first, or else I will surely come and remove your lampstand out of its place--unless you repent.

I tell you that I am about to cast her upon a bed of sickness, and I will severely afflict those who commit adultery with her, unless they repent of conduct such as hers.

in order that no one should be allowed to buy or sell unless he had the mark--either the name of the Wild Beast or the number which his name represents.